Due to increase in environmental problems of the construction industry alternative technologies are emerging. A concrete is used around the world is second only to water. The making of ordinary Portland cement support 5 to 7 percent of total green house gas emission. It also takes large amount of energy .Hence it is necessary to find alternative to cement .Fly ash is a product of coal procured from thermal power plant. It is also good in silicon and alumina. In this experiment the fly ash is used to prepare the geo polymer concrete.geopolymer is a material resulting from the reaction of source materials that is rich in aluminum and silicon. One such material is GEOPOLYMER CONCRETE. It uses a material like fly ash as binding material in place of cement.

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International Journal of Civil Engineering and Technology (IJCIET)
Volume 7, Issue 3, May–June 2016, pp. 347–353, Article ID: IJCIET_07_03_035
Available online at
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=3
Journal Impact Factor (2016): 9.7820 (Calculated by GISI) www.jifactor.com
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication
STRENGTH PROPERTIES ON FLY ASH
BASED GEO POLYMER CONCRETE WITH
ADMIXTURES
A.Iftiqar Ahmed
PG Student, Department of Civil Engineering, Siddarth Institute of Engineering and
Technology, Puttur, Andhra Pradesh, India.
Dr. S. Siddiraju
Professor and Head, Department of Civil Engineering, Siddarth Institute of
Engineering and Technology, Puttur, Andhra Pradesh, India.
ABSTRACT
Due to increase in environmental problems of the construction industry
alternative technologies are emerging. A concrete is used around the world is
second only to water. The making of ordinary Portland cement support 5 to 7
percent of total green house gas emission. It also takes large amount of energy
.Hence it is necessary to find alternative to cement .Fly ash is a product of
coal procured from thermal power plant. It is also good in silicon and
alumina. In this experiment the fly ash is used to prepare the geo polymer
concrete.geopolymer is a material resulting from the reaction of source
materials that is rich in aluminum and silicon. One such material is
GEOPOLYMER CONCRETE. It uses a material like fly ash as binding
material in place of cement. Here the alkaline solution, sodium silicate and
fly ash combine to form a gel which binds fine and coarse aggregates. Since
geopolymer concrete is a new field, the guide lines from the BIS are yet to
be created. A trail has been made to find out an optimum mix for fly ash
based geopolymer concrete. The size of concrete cubes 150X150X150 mm
was casted. geopolymer concrete is free from cement. A grade chosen for the
investigation are M20.The mix are designed for molarity of 8M, 12M,
16M.we are calculated the slump values and compressive strength values. The
compressive strength is found at 7 days and 28 days. By comparing the
geopolymer concrete with conventional concrete is more advantageous,
economical and eco friendly.
Key word: Fly Ash, Geopolymer Concrete, Sodium Hydroxide (NaOH),
Sodium Silicate (Na2SiO3), potassium hydroxide (KOH).

2. A.Iftiqar Ahmed and Dr.S.Siddiraju
http://www.iaeme.com/IJCIET/index.asp 348 editor@iaeme.com
Cite this Article: A.Iftiqar Ahmed and Dr.S.Siddiraju, Strength Properties on
Fly Ash Based Geo Polymer Concrete with Admixtures International Journal
of Civil Engineering and Technology, 7(3), 2016, pp.352–358.
http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=3
1. INTRODUCTION
The alkaline liquid reacts with the silicon (Si) and the aluminum (Al) in by-product
materials such as fly ash to produce binders. The chemical reaction that takes place in
this case is a polymerization. Geopolymer concrete is concrete which does not require
any Portland cement in its making. The two main constituents of geo polymers are the
source materials and the alkaline liquids. The materials used for geo polymers lies on
alumina-silicate rich in silicon (Si) and aluminium (Al). Alternatively, by-product
materials such as fly ash, silica fume, slag, red mud, etc could be used as source
materials. Liquids are from soluble alkali metals that are usually sodium or potassium
based. The alkaline liquid used in polymerisation is a mixture of sodium hydroxide
(NaOH) or potassium hydroxide (KOH) and sodium silicate.
2. MATERIALS USED
2.1. Fly Ash
The Fly ash is residue resulting from the burning of ground or powdered coal, which
is taken from the boiler by flue gases. Fly ash can be used in Portland cement
concrete to increase the performance of the concrete. Fly ash is one of the remains
generated in burning, and contains the fine particles that flow with the flue gases.
Figure1: Fly Ash

3. Strength Properties on Fly Ash Based Geo Polymer Concrete with Admixtures
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2.2. Coarse Aggregate
Coarse aggregate are an inert materials used in construction. Hard stones are crushed
in required sizes. The material that is retained on IS sieve of size 4.75 is called coarse
aggregate. These aggregates combine with cement and fine aggregates with water to
form concrete. Coarse aggregates of sizes 10mm and 20mm are used in this study.
The properties of coarse aggregate as shown in Table 1d
Table 1 Properties of Coarse Aggregate Aggregates
Property
Coarse Aggregate
20mm
Coarse Aggregate
10mm
Fineness modulus 8.12 8.12
Specific Gravity 2.71 2.71
Bulk Density
1533.30
Kg/m3
1512
Kg/m3
Percentage of voids 44.15% 47.42%
2.3. Fine Aggregate
Fine aggregate is one which passes through IS sieve 4.75mm sieve and retained on 75
microns. It should not be soft; it should be free from organic matter and clean. Fine
aggregate should not contain clay balls, alkalis, salts, coal, and decayed material. The
silt contents should be below 4%. The properties of fine aggregate are shown in Table
2.
Table 2 Properties of Fine aggregates:
Property Fine Aggregate
Fineness modulus 3.40
Specific gravity 2.61
Bulk Density 1250 kg/m3
Percentage of voids 51.24%
2.4 Sodium Hydroxide Solution
The alkaline activator used in geo polymerisation is a mixture of sodium hydroxide
and sodium silicate. The alkali percentage is a significant factor in controlling the
leakage of alumina and silica from fly ash particles, following geo polymerization and
mechanical properties of hardened geopolymer. The gel composition calculated in the
sample animate with the mixture of sodium silicate and NaOH is increased in Na and
Al [1].
This solution is having of solute and solvent. Solute is the immerged substance
and solvent is the substance in which the solute is dessolved.A solute can be liquid or
solid. In NaoH solution sodium hydroxide is the solute that is in solid state and water
is the solvent that is liquid form. Notice that solute being a solid and is calculated in
terms of weight in (grams) .And the solvent water is denoted interms of volume.

4. A.Iftiqar Ahmed and Dr.S.Siddiraju
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Figure 2:Sodium Hydroxide flakes
2.5 Sodium Silicate Solution
Open porosity can be drawn and is readily filled with gel as soon as the liquid phase
is able to mix with the ash particles. The liquid phase is vital as a fluid transport
medium allowing the activator to reach and act with the fly ash particles.
3. METHODOLOGY
3.1. Preparation of Alkaline Solution
In this experiment the compressive strength of geo- polymer concrete is examined for
the mixes of varying molarities of Sodium hydroxide (8M, 12M, and 16M). The
molecular weight of sodium hydroxide is 40. To prepare 8M i.e. 3 molar sodium
hydroxide solutions, 120g of sodium hydroxide flakes are weighed and they can be
dissolved in dissolved in distilled water to form 1 litre solution. For this, volumetric
flask of 1 litre capacity is taken, sodium hydroxide flakes are added slowly to distilled
water to prepare 1liter solution. The weights to be added to get required molarity are
given in Table 2.
Table 3 Weights of NaoH Flakes
RequiredMolarity
Weights in gms of
Sodium hydroxide flakes
8M 350
12M 520
16M 640

5. Strength Properties on Fly Ash Based Geo Polymer Concrete with Admixtures
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3.2. Proportioning of Geo-Polymer Concrete
The fly ash, fine aggregates and coarse aggregates are mixed in a container and then
the alkaline solution was added to prepare the geopolymer concrete. The geopolymer
concrete is poured in 100 mm cube moulds. The Geopolymer concrete is in dark
colour with shiny appearance. The proportions of mixing are as given in Table 3. As
per no code provisions for the mix design of geo- polymer concrete, the density of
geo-polymer concrete is assumed as 2440 kg/m3
. The other values are found by
assuming the density of concrete.
The aggregate takes place the volume is assumed to be 65%. The quantities of all
ingredients are kept constant as given below Table 3 except the molarity of NaOH is
changed in the each mix. The other method used in the making of normal concrete is
included to prepare geopolymer concrete. First, the fine aggregate, coarse aggregate
and fly ash are mixed in dry condition for 3-4 minutes and after that the alkaline
solution which is an addition of Sodium hydroxide solution and Sodium silicate
solution with super plasticizer is mixed to the dry mix.
The mixing is prepared about 6to8 minutes for correct bonding of the materials.
After the mixing is done, the cubes are casted by providing with good compaction.
The size of the cube which is taken is of size 100*100*100 meters. the curing of geo-
polymer concrete cubes, the two methods are applied, one method is by kept the cubes
in hot air oven and by keeping the cubes in direct sun-light. In the oven curing, the
cubes are removed and kept in oven at 60o
c for an hour. Then the cubes are removed
and kept in oven at 50o
c for 7days. In the sun light curing, the cubes are removed after
1 day of casting and they are kept in the direct sunlight for 7 days. The mix
Proportions of geo-polymer concrete as shown in Table 4
Table 4 Mixing Proportions of Geo-Polymer Concrete
Fly ash
Kg/m3
Fine
Aggregate
Kg/m3
Coarse
Aggregate
Kg/m3
NaOH
Solution
Kg/m3
Na2Sio3
Solution
Kg/m3
Extra
Water
Kg/m3
SP
Kg/m3
395.52 555.42 1294.5 46.12 113.65 40.65 12.85
3.3. Compressive Strength of Geo Polymer Concrete
The cubes are placed in compressive testing machine to found their compressive
strength to the age at 7 days of curing. The figure 3 and figure 4 are indicating the
compressive strength develop with molarity of NaOH. (3M, 5M, 7M and 9M) for the
specimens which are cured by hot air oven and by direct sun light at the age of 7days

6. A.Iftiqar Ahmed and Dr.S.Siddiraju
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Table 5 Compressive Strength of Geo Polymer Concrete
Specifications Avg. Ultimate load In
kN
Avg.Compressive Strength
in Mpa
FR M8 Cs A7 123.72 6.24
FR M8 Ch A7 363.25 17.25
FR M12 Cs A7 178.53 9.65
FR M12 C h A7 482.35 22.35
FR M16 Cs A7 196.25 9.65
FR M16 Ch A7 490.2 22.5
Figure 3 The Compressive Strength at Age of 7 days in Ambient Curing
Figure 4 Compressive Strength at Age of 7 days of Oven Cured
0
0.2
0.4
0.6
0.8
1
1.2
1.4
8M 12M 16M
7 days
Concentration of NaOH
CompressiveStrength,MPa
0
0.2
0.4
0.6
0.8
1
1.2
1.4
8M 12M 16M
7 days
Concentration of NaOH
CompressiveStrength,MPa

7. Strength Properties on Fly Ash Based Geo Polymer Concrete with Admixtures
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4. CONCLUSIONS
 We calculated that the compressive strength is increased with the Increase in the
Molarity of sodium hydroxide.
 For 7 days of curing the increased value in the compressive strength is significant.
 Compare to hot air oven curing and curing by direct sun light, oven cured specimens
gets more the compressive strength but sunlight curing is conveniently good for
practical conditions.
REFERENCES
[1] Dody M.J. Sumajouw, Wallah, Studies on Fly Ash Based On Geo Polymer
Concrete Geo Polymer: Green Concrete and Development Solutions.
[2] Shetty MS, The Concrete Technology Book, S. Chand Publishers.
[3] Strength and durability of fly ash based geopolymer concrete, Dr Chandra
Shekhar Reddy , Final year dissertation, the Curtien University, Perth Australia
[4] Sameer Vyas, Neetu Singh, Rp Pathak, Pankaj Sharma, Nv Mahure and Sl Gupta,
Behaviour of Alkali Activated Fly Ash-Based Geopolymer Concrete On Thermal
Activation International Journal of Civil Engineering and Technology, 5(4),
2014, pp.28–36.
[5] Sameer Ul Bashir, Effect of Alkali Materials On Geo Polymer Concrete
International Journal of Civil Engineering and Technology, 6(1), 2015, pp.1–13.
[6] Pateel Alekhya and Mr. S. Aravindan, Experimental Investigations on
Geopolymer Concrete International Journal of Civil Engineering and
Technology, 5(4), 2014, pp.1–9.
[7] T.V. Srinivas Murthy and Dr. Ajeet Kumar Rai, Geopolymer Concrete, An Earth
Friendly Concrete, Very Promising In The Industry International Journal of Civil
Engineering and Technology, 5(7), 2015, pp.113–122.